520 vintage

My Trek 520 is rainforest green also and it is a 2004. That is the only year I know of that Trek manufactured 520's that color. As of a few years prior it was slate grey. If it is new enough to have V-brakes I'd say it's safe to say it's relitively new, this is a rare feature on road bikes and wasn't common technology until the late 90's.

http://www.vintage-trek.com/
serial number BS 6102...
I'm not sure that the serial number system stated on this site applies, the second letter (S), would not apply to a month of the year.